Machines are known in the prior art to provide for the automatic installation of fasteners in workpieces such as the insertion of a rivet into a hole with subsequent upset of the rivet tail, as well as the insertion of a threaded fastener into a hole with subsequent supply, installation application and torquing of a threaded nut to the threaded fastener. In the case of installation of threaded nuts, the prior art machines have heretofore experienced a number of troublesome areas of operation that result in frequent shutdown for repair or servicing due to inherent limitations in certain mechanical systems and reduced reliability in other areas of nut handling from the supply source to its installation. For example, the use of plastic tubing in the nut supply path produces inherent limitations in the length and movements of plastic tubing due to their propensity of bending or kinking under certain conditions whereby the effective cross-sectional area is so reduced that nut passage is retarded until geometry of the tubing is realigned.
Another typical example of difficulties that can be encountered in some of the prior art machines is the final nut torquing arrangements of gear trains which lack some degrees of stability and accuracy due to inherent inability to attain variation in final torque values without adjustment or recalibration of the gear train mechanical system or the torque motor.